Referring to FIG. 1 for the manufacturing technology of a traditional opposite discharge AC type (AC) plasma display panel (PDP) 10, different functional layers are formed on two glass substrates 11, 12, and the peripheries of the two glass substrates are sealed o form a space between the two glass substrates, and a special gas mixed according to a specific proportion such as helium (He), neon (Ne), xenon (Xe) or argon (Ar), etc is filled in the discharging cell 13 within the space between the two glass substrates. In the structure of a plasma display panel as shown in FIG. 1, the substrate facing the viewer is a front substrate 11, and the front substrate 11 at its inner side sequentially includes a plurality of parallel transparent electrodes 111, auxiliary electrodes (or bus electrodes) 112, dielectric layers 113, and protective layers (such as manganese oxide, MgO) 114, and the corresponding rear substrate 12 sequentially includes a plurality of parallel data electrodes 121, dielectric layers 124, protective layers 125, barrier ribs 122, and evenly coated phosphors 123 (which could be red, green, or blue phosphors), such that if a voltage is applied to the electrodes 111, 112, 121 at related positions, the dielectric layers 113, 124 at the corresponding positions will discharge electricity in the corresponding discharging cells 13 formed between the adjacent barrier ribs 122, enabling the phosphors 123 to emit the corresponding color lights.
In the AC discharge plasma display panel 10 as shown in FIGS. 1 and 2, the electrodes on the front substrate 11 generally go through spluttering and photolithography to form a plurality of mutually isolated and horizontally aligned transparent electrodes 111 on the inner surface of the front substrate 11, and then go through deposition (or spluttering) and photolithography or printing process to form the bus electrode 112 on the transparent electrode 111, such that the bus electrode 112 reduces the line impedance of the transparent electrode 111. The transparent electrode 111 (including bus electrode 112) and the data electrode 121 disposed at corresponding positions of the rear substrate 12 form two opposed electrodes, so that if a voltage is applied to these electrodes 111, 121, their dielectric layers 113, 124 in the corresponding discharging cells 13 will carry out opposed discharges, and the mixed gas therein will discharge electricity to produce an ultraviolet (UV) light and activate the phosphors 123 coated on the discharging cell 13 to emit three visible lights: red, green, and blue and display images. The traditional AC discharge plasma display panel 10 of this sort is also known as “opposite discharge plasma display panel”.
In the foregoing opposite discharge plasma display panel 10 as shown in FIGS. 1 and 2, the data electrode 121 on the rear substrate 12 is disposed at the bottom of the dielectric layer 124 and parallel to the corresponding transparent electrode 111 (also called “scan electrode” or “sustain electrode”) disposed on the front substrate 11 and vertically coupled to the position of each discharging cell 13. A shadow mask 20 is attached onto the protective layer 125 at the top of the dielectric layer 124, and the space corresponding to each shadow hole 21 on the shadow mask. 20 forms each discharging cell 13, and the metal conductor around each shadow hole 21 serves as a barrier rib 122 for each discharging cell 13 and is formed by enclosing the adjacent barrier ribs 122 in the corresponding discharging cell 13. The phosphor 123 is coated evenly onto the wall of the grid barrier rib 122, and the coating area of the phosphor 123 is increased to effectively improve the luminescence efficiency of the plasma display panel 10. However, the rear substrate 12 of the foregoing opposite discharge plasma display panel 10 is attached to the barrier rib 122 that is formed by the grid metal conductors disposed around each shadow hole 21 of the shadow mask 20, such that after the front substrate 11 is attached on another side of the shadow mask 20, and the peripheries of the two glass substrates 11, 12 are sealed, each discharging cell 13 will not discharge or fill air easily due to the grid design of the barrier rib 122.
To improve the efficiency of discharging and filling air, the traditional shadow mask 20 adopts a double-sided etching method as shown in FIG. 3 to etch the required barrier ribs 122 and shadow holes 21 on one side of the shadow mask 20 and a plurality of air channels 23 on the other side of the shadow mask 20 and at the positions corresponding to the shadow holes 21 as shown in FIG. 4. Each air channel 23 is interconnected to the discharging cell 13 through the shadow hole 21 for effectively solving the air discharging and filling problem of the discharging cell. However, this method still has the following shortcomings:    (1) In the double-sided etching method, the process of etching the barrier ribs 122 and the air channels 23 on both sides of the shadow mask 20 is quite complicated, and the level of difficulty is relatively high, and thus incurring a higher manufacturing cost.    (2) In the double-sided etching method for making the shadow mask 20, it is not easy to control the width and depth of the air channel 23 in the etching process as shown in FIG. 5. To ensure that the etched air channel 23 will not affect the size of the shadow hole 21, the etching depth of the discharging cell 13 is generally reduced to increase the remaining thickness tm of the shadow mask 20 for etching and producing the air channel 23. However, if the etching depth of the discharging cell 13 in this method is decreased, the coating area of the phosphor will become less, and thus causing an adverse effect to the luminescence efficiency of the opposite discharge plasma display panel.